1. Field of the Invention
The present invention relates to the technical field of 3D (3-Dimensional) displaying, and in particular to an operation method of shutter glasses based 3D display devices.
2. The Related Arts
The conventional glasses based 3D displaying techniques generally supply signals of left-eye and right-eye frames to a liquid crystal panel in an alternate manner to respectively drive the liquid crystal panel to form thereon left-eye and right-eye images, which cooperate with illumination of a scanning back light unit (BLU) and timing control of shutter glasses to stimulate left and right eyes with left-eye and right-eye signals respectively to thereby making a user perceive a 3D image. Since the response speed of a liquid crystal screen is excessively slow, the timing of activation of the BLU and opening of the shutter glasses and the duty time thereof must be adjusted to reduce the influence of crosstalk between left and right eyes. However, such control of timing reduces the activation time of the backlight and the shutter glasses, resulting in reduction of luminance or flickering.
As shown in FIG. 1, a timing chart of a conventional shutter glasses based 3D display device is shown. The vertical axis indicates vertical positions on a panel of the display device and the horizontal axis indicates time. The BLU of a regular 3D display device is divided into vertical blocks and thus a scanning operation is performed to sequentially, in a top to down manner, control the activation and duty time of each block of the back light unit (an example of five blocks, S1, S2, S3, S4, S5, being given in FIG. 1). The time period for left-eye and right-eye signals of the display device are respectively T1 and T2, each representing the time period of a frame. A frame time is composed of the driving time of a signal (the signal being from the first line to the last line) and time of blanking. The signal sequentially provides a necessary driving voltage to each line of the liquid crystal panel in a top to down manner. After a pixel receives the driving voltage and is charged, the liquid crystal starts to respond. Due to the arrangement of pixel and the viscosity of liquid crystal, there is a period of response time, L0, for the liquid crystal to completely reach a desired stable condition, namely the target luminance signal for each of the left and right eyes. Further, an additional important parameter of the shutter glasses based 3D display device is the opening and closing time of the left and right eyes of the shutter glasses. An overall adjustment must be made on the timing of the shutter glasses, in combination with the scanning time of each block of the back light unit, the response time of the liquid crystal, and the blanking time, to realize optimization of the 3D effect of the liquid crystal display, so that the left-eye and right-eye signals will not overlap and cause after image. Otherwise, as shown in FIG. 1, during the opening time period of the left eye of the shutter glasses, the signal to the liquid crystal associated with block S1 has already been switched from a left-eye signal to a right-eye signal, and this causes the right-eye signal to be seen during the opening time period of the left eye of the shutter glasses. Consequently, at the time when block S1 is in operation, the left eye of the shutter glasses will see the after image of the right-eye signal in a short period of time. Further, as shown in FIG. 1, the left eye of the shutter glasses has an early opening time and blocks S2, S3, S4, and S5, when in operation, supply left-eye signals. Meanwhile, due to the slow response of liquid crystal, blocks S2, S3, S4, and S5, when in operation, are subject to influence, to different extents, by the previous right-eye image, resulting in interference of after image.
Further, keyboards are used outdoors more and more frequently. However, for outdoor or public site use, due to more dust existing in the outside environments, such dusts may easily get into the keyboard through gaps present in a device surface and may get chronic accumulation, making it hard to be cleaned and eventually affecting the performance and lifespan of the keyboard.